Final: Cell-Cell/Cell-ECM

Question 1

Do cadherins have homophilic or heterophilic interactions? Integrins?

Answer 1

cadherins: homophilic (bind to same cadherin type)
integrins: heteropihilic (bind to ECM components)

Question 2

Are cadherins or integrins calcium dependent?

Answer 2

cadherins are calcium dependent, integrins are often modulated by calcium or magnesium but not strictly dependent

Question 3

What type of interactions is cadherin adhesion modulated by? integrin adhesion?

Answer 3

cadherin: cis clustering and signaling pathways
integrin: inside out and outside in signaling pathways

Question 4

What is loss of E cadherin an indicator of? What happened with E cadherin and the gastric cancer experiment?

Answer 4

invasive cancer
E cadherin was at intracellular boarders of normal gastric glands but no E cadherin at boarders of invasive carcinoma cells

Question 5

What do high vs low affinity E cadherins want to do?

Answer 5

high: grab onto calcium tightly so they all go to the middle
low: less agressive so they get kicked to the outside

Question 6

What is outside in signaling regarding integrins? What’s the mechanism?

Answer 6

signals orient from ECM and are transmitted into the cell through integrins, triggered by the binding of integrins to ECM ligands
ECM binds integrin, integrin transmits signal inwards, talin links to cytoskeleton, cellular response occurs

Question 7

What is inside out signaling regarding integrins? What’s the mechanism?

Answer 7

signals from within the cell modify integrins to increase or decrease their affinity for ECM ligands, triggered by intracellular signals
intracellular signal, talin binds integrin, integrin activates, ECM adhesion